Telephone-exchange system



Novgg, 1952-7.

J. w. GOODERHAM TELEPHONE EXCHANGE SYSTEM 3 Sheets-Sheet l Filed July20. 1923 Nov. 29, 1927. 1,650,708 M J. W. GOODERHAM TELEPHONE EXCHANGESYSTEM Filed July 20, 1923 5 Sh Code Nw. 29, 192%?. A 1,650,708

` J. W. GCODERHAM TELEPHONE EXCHANGE SYSTEM Patented Nov. y Z9, i927,y

Y i Y ,liid

at Ac; riff-cn.

ci rnnnenonnfnncnanen sYszrni/i.

i application sied nay zo, 1923 sensi No.' 652,678; y

This invention relatesvto telephone s-yS- tems andV more particularly tomeans` in such` systems for controlling indicatingdecurrent impulses of'va rious charac` and apparatusfor determining the. charac-` teristicsofsuch impulses.. i

This invention constitutes.animprovement i over UQ S. Patent No.1,438,743 granted to Edgar Hl ClarlnDecember 12, 1922"Whicl1 relatestoatelephonersystemin which means are providedby which an operator may beinformed visually of the number of a-Wanted subscriber.` The means for`so doing includes regsters which may be set in accordance With thecalled number, an impulse trans mitting switch and an organization ofre-l lays and sition. Y v .y Q

Ovvingto the irregularities introduced in the commercial mamifactureandadjustment of parts which go to makeup the impulse transmitting switch,it is possibleinipractice that bri efv false `impulses lmay occur.between the pulses intended to `be sent, Whichpulses may be sufficienttolcause the incorrect operation of the indicators. These ,falseimpulses can, ofcourse, beeliminated by perfectly adjusting each switch,butin a telephone system employing hundredsof these switches, such aprocedure wouldbe decidedly uneconomical. i l

Accordingly, a feature of the present in vention is the eliminationfofsuch false pulses bythe use of af novel arrangement of the impulsecontrolling and transmitting means.

A.-further feature ofthe present invention lies in the provision ofindividual circuits for the transmission of impulses of di'erentcharacteristics as far as the trunk circuit. lnipulses of allAcharacteristics are then transmitted over said trunk circuitV rlliis andother features of the invention will appear in the accompanying drawingand description together with the Yappended claims. c f

The drawings with Fig. 2 placed below F l and with llig. I placed at the:right of ll'igQ diagramniatically represent portion of ntfeiephonesystem employing the present invention. lfig.. 1 shows acalling. subscribe lindicators at the operatorspoers substation and,lline With brushes of a district vselector at an operatorspositl'omacalling plug andgack at a second operators` position and a` calledsubscribei"s`v substation: A

apparatus and line,` y Nithin the small' dot` ted rectangle at the-lefthand.; side of: Figfl, there are shown the brushes of a cordfin'derswitch Whichv operates to connect anidle" `Sending device to the cordcircuit which has beenconnectedto the calling line." Within the largedottedrectangle att-he right handelde of Fig. 1, there are shown anoperatorskey setand the `registers-ot the sending device' forcontrolling the transmission.ofimpulses to the number indicatingdevice.VVithinfthe larger dotted enclosure at the left ofFigi l, there is shownan impulse transmitting device which, under the controlof` theregisters,V transmits various combinations ofimpulses to actuatethenumber indicating device. i

y lnliig. there are shown the viniousre,-` lays which cont-rol theliglitingof theV proper stations lamp as WellV as the switching relayswhich Operate to controlthe actuation ofthe thousands, hundreds, tensandunits indicat. ing" devices in propersequence.I c y 1 F ig. 3 in itslower-right handcorner shotvs" the lamps and controlling relays for`indil' cating'thethousands digit; at the'lcyver, left hand cornert liehundreds; at the upper left hand corner, Vthe tens; andatthe upper righthand corner, the units lamps and, the relays for controlling them.

4 In this disclosure, the showingv of the apparatus and circuitsfor-selecting the second or B operatonsposition.has beenabbreviated butit may be of the character of the sys-4 tem Y disclosed in patent toLundell `No. 1,168,319, January. 1S, 19164 or it may. ibesimu ilar tothe system shoWnin the patent to E; H, ClarkNo..1334,7357of Marchf23,1920.l

The trunk selecting; switchfreferrcd to in the description may` be of;the type illus` trated in the patentI to Craft and Reynolds 1,123,696of. January 5i 19`15,.althoughit Will be readily understood that anyautomatic selector switch can beemployed in'` thissyss teniv Withoutdeparting from thespirit of the invention. i

lnA the' description, reference made' .to sequence switches andregisters, the structure of which may befsiinilar toithat shownintliepatent Jfri-Reynolds and Baldwin l-,lQfTOSV of February 9, 1915. It isto be noted, however, that a revolution of the impulse sequence switchis divided into twenty )osi-v ti'onsof eighteen degrees each instead othe usual arrangement of eighteen positions of twenty degrees each. Thisis merely a matter of convenience and introduces no change in the`operation ot the switch.

It is also to be noted that this invention ually applicable to systemssuch as that dise osedin U. S. Patent 1,395,977 granted to F. A. Stearnand F. J. Scudder, November .1, 1921, that is, to systems in which theregisters 4take the form of step-by-step i, switches or areset undertheV control of the fsubscriber without the intervention of an operator.

. lIn' general, the system of the Vpresent dis- 'closure comprises a setof operators keys which controls sequence switch registers, all.

' oflvhieh are shownin the dotted rectangles Y at the right of Fig. 1; aswitching device tor sending impulses as determined by the sequenceyswitch registers as shown in the larger left hand dotted enclosure inFig. l;

` andan arrangement of relays for receiving im ulses as shown in Figs. 2and 3.

n Fig. 2, there are shown three relays in series 201, 202 and 203 whichrespond directly to'the transmitted impulses. These relays in turncontrol a combination of two pulse switch to makean additionalrevolution, additional registers being provided. As themeans for doingso forms no part ot' the present invention, the disclosure hasbeenlimited, tor simplicity, to a five digit number.

` There is provided -a set of indicating lamps for each'one of thedigits of the called num- .,ber, each set of lamps being controlled bya. sety oflamp controlling relays as shown in Fig. 3. The set 321, etc.,controls the thousands lamps,"the set 331 etc., controls the hundredslamps, the set 341, etc., controls the tens lamps and the set 351, etc.,controls the units lamps. As shown in Fig. 2, the set 262, ete.,controls the. stations lamps.

`The impulses transmitted by the sequence. switch 114 in Fig. 1 are inthe nature ot a code, which consists essentially of heavy negative imulses between which may be interposed lig t positive impulses, the heavynegative impulses being superimposed on light negative impulses whichserve as switching impulses. may be omitted.

The positive impulses are produced by The'V positive impulses currentfrom grounded battery, tlowim.y

through resistance 143 and overa parallelk path through low resistance1li and cams controlled by sequence switch 114 and cam' contact-s closedby the sett-ing of the registers to brush 10G. Thus in etect,lswitchingcams 131 to 133 and register cams 151, 153, 156, 158 and 159 togetherwith battery and resistance 1,42 form a generating device for positiveimpulses only, while switching cams 145 to 149 and register cams 150,15T, 152, 154 and 155 together with battery and resistance 144 form agenerating device for Y negative impulses only.

Attention is directed to the fact that the paths followed by thepositive impulses from battery to brush ^are entirely sep'- arate fromthose followed by the negative impulses from battery to brush 100. In imease, does the same cam serve for bothnega tive and positive impulses.While battery throughhigh resistance 143 is continuously connected tothe side of the line leading to brush 106, it produces no effect atthetime ot sending positive pulses, being shunted out by ground on cam140.l

In the disclosure of the above mentioned Patent No. 1,438,743 to E. H.Clark, it may be seen that only two sequence switch cams are used fortransmitting all the heavy pulses for eaclrdigit, one on the registersequence switch and one on the impulse sequence switch. Therefore, ifthe cams on the impulse sequence switch, which feed the successivepulses that go to make up the code for a given digit, are not properlyadjusted, but overlap a little, it is possible tor heavy currentintended for the preceding or succeedingr impulses to find a momentarypath over the line in the opposite direction. thusy causing a momentaryheavy pulse whereone may not have been intended. rlhe .separation of theleads from battery, through the impulse switch and the registers to theopposite sides ot the line, in accordance with the present invention,entirely eliminates the. possibility ot the current for the negativeinipulses find` ing a path over the positive cams to tlie line. Cainoverlap may prolong a pulse but it cannot feed it out to the wrong sideof the line. It is also to be noted that the positive cams of theimpulse switch are closed from slightly before the time of the firstpositive pulse of a digit to slightly after the time for the second Ilmell

positive-pulse of a digit, thus preventing any l surge oitcurrentL whichmay occurl due to the closureof the battery leadV from interferingwithan open or non-pulse periodi Attention is alsocalled to the fact thatthe circuit for the pulses are further separated.

by having'the circuitstor the iirst pulse car* ried through one cuttingof theregister and: impulse switch cams and the second pulse thro-ugh asecond cutting on these"` cams, thus additionally insuring the"individuality ot'- the pulses. V i

The code-ot impulsesfis showndiagrammatically inthe upper part ci? Fig.2: Positive im mises are re resented b a )lus sign As will1 hereinafterappear, the lamp con trolling relaysr such as^321, 322, 323, and areenergizedwheneveran impulse ot poen tivecurrent or an impulseot heavynegative current is transmitted and thus thehcodes diagrammaticallyshown give anf indication of which lamp controlling relays willbeenergized, it being noted that the-flinal digit ot' the numbersapplied'to the relaysin eachl set is the same as'tlie number atthe'headloli 'the corresponding column in the code shown in Fig, 2. yFor instance, in theinumericalfcode, the series of` impulsesfortlle'digiu c`on-l sists ot'` first, al positive impulse, second', `alight negativeV impulse, third, ay blank, and :tour-th, aheavy'negativeimpulse. *Asindicated, the first and fourth relays will beenergized according to this code. The stations codecorresponds to thenumerical code eX- ceptthatno initial positive impulsesare sent.

The method of establishing al connection from a calling substationasshownf at' 101 to a called substationl as shown at 102 will now bedescribed.. `When the calling sul scriber removes his receiver' `tromhis switchL hook, a signal (not shown) is lighted fat an operatorlsposition. This operator, known as an A operator, thereupon connects thecord circuit conductors 103 and" ,106ir tothe callingy line manually orby anyother suit able means. is soon as the A; operator has connectedthe cord circuit tothe `calling line, a cord finder whose'ljrushes areindicatedE at llland lotoperates to connect anidlesend`- -ingA devicevwithV they cordI circuit taken for use. `When theoperator connects thecord circuit to the callingdv line, she ascertains theI number ofthewan-tedsubscriber andl proceedstoset up this nuinben on the keyboard: otliersending device.-

`Let us assume that the-wantednumber is itdistation lV. 'IlheV operator.will1 then depress the corresponding stations, thousands, hundreds,tens' and units keys 1n response to which the associated sequence switchregisters will* be movedV and the sta tions register 109 will come torest in posi? tion 7, the thousands-register 11() will stop at positionfl, the hundreds register 111 .in

position 5, the tens register 112 in position'l 6 and theunits register113` in position It will be Vassumed.that thefautomatic trunk selecting'switch whose brushes are lindicated by the numerals 107 and.lOSfhas`been eet to: select the proper` trunk for -connetting Vthe callingsubscriberV with theB oper-atene position at the ollicein.` which thewanted line terminates. 1 1t will be'assumed that the; sequence Aswitchassociated with this trunk selecting switch hasbeen moved" into position11. i

fitter the sending devicelhas been set, and when the trunk selectingswitch hasgbeen operated to extend-t-hecalling `line` tfothe4l'operators position at; the desired-chics, the sequence switchassociated with the cord lindcr will bein position i Where acircuit willhe established to venergize relay11f. This circuit-may be4 traced fromground, sequence switclr cam 116, winding ot" relay 117, sequence,switch camy 118 (position 11)l brush 105, upper. contact ot sequenceVswitch cam 119, brush `108, lower armatureand back.

contactotl relay 120,`lower lett hand wind- Y ing ofy repeating coill1211, winding of relay 123"to groundedY battery. Relays 117 and 123? areoperated by"currentf flowing over thiscircuit. Relay 1172by theattraction of itsfarmature closes afcircuit `from ground, armature andiront contact ot relay 117, winding ot relay 115 to grounded batterywhereby reluy"1i15 is energized.` At. the front Contact andarmature otrelayy 123, a circuit is closedVt'iom ground back contact and armatureof relay 125, lampi 1216, to grounded battery; loampl126, in lighting,

indicates to the manual operator that a call is awaiting attention andalso indicates the trunk` over whichthe call has beenextended.

The manuall operator) thereupon 'depresses key 127 to'associate'thenumber indicating' device with the trunk'over which thecall has been extended; l i Upon the depression ot key 127, av circuit`is closed from ground, winding ot relay 120,y

contact otkey127, conductor 12S, winding ot relay 20()to'groundedbattery. Relay 2.00

attractsits armatures, to apply ground' to the various controlling leadsol the number indicating device:` Art the Sametime, relay 120 attractsits armatures and at its lower armature interrupts thel energizing'circuit of relay 117. With this relay deenergizedi lil() a circuit isclosed from ground, through its armature and back contact. armature andfront contact of sloW-to-release relay 115, magnet of sequence switch114 to grounded battery to move the sequence switch 114 out of position1 whereupon it Will, under the control of its master contact 124, rotatethrough its various operating positions back to position '1, duringwhich a complete set of impulses is transmitted to the relays 201, 202,and 203. Relay 203 is marginal and responds only to impulses o'l heavycurrent, relay 201 respondsonly to positive impulses, and relay 202yresponds only to negative impulses, the 'armature of these relaysk beingnormally retracted.

As has been mentioned, vno positive pulses are sent out in the firstperiod of the train for the Vstations code. Accordingly the. uppercontact of cam 139is not closed during the time that the sequence switch1147is passing through positions'l-l-l/2 and the correspondingconnection to positive cani 150 of stations register 109 is omitted.

When sequence switch 114 moves into position 2, a circuit is closed fromgrounded battery, throughhigh resistance 143, and

in parallel through loW resistance 144 over theupper Contact of cam 145,and lower cont-act of negative cam 150 of stations register 109 to cordfinder brush 106, thence by way of the upper contactof cam 135, trunkselector brush 107, upper armature and front contact of relayr120,conductor 204, Winding of-marginal relay 203, Winding Yof negativelypolarized relay 202, Winding of positively polarized relay 201,conductor 134,'lower armature and front contact of relay 120, trunkselector brush 108, upper contact ofV cam 119, cord finder brush 105,upper contact of cam 140 to, ground. Since the impulse circuit extendsthrough low resistance 144, marginal relay 203 'is energized and sincethis impulse is negative, relay 202 attracts its armature and closes acircuit from grounded battery, left Windying of relay 209, Winding ofrelay 207, lett armature and baclccontact of relay 209, armature andfront contact of relay 202, conductor 208, outer armature and lirontcontactof relay 200 to ground. The left Winding-of relay 209 is aholding Winding and able only to hold the armatures of this relayattracted when once they have been actuated by the right or pull-upWinding of this relay. Thus, relay 209 does not attract its armaturesbut, relay 207 does attractv its armatures in this circuit. inner rightfront Contact and armature ot thisrelay, a circuit for the right Windingof relay 209 is closed, but this winding is short-circuited at this timeas fully. explained later.

At the outer right front contact and armature of relay 207, anvenergizing circuit for relay 206 is completed from grounded battractsits armatures and at its inner right front contact and armature closesan energizing circuit for relay 210 but this last mentioned relay isshort-circuitcd at this time and does not' attract its armatures. Due tothe energization ofanarginal relay 203 together with the cncrgization ofrelay 202, a circuit is closed for stations relay 262 extending fromgrounded battery, left winding of relay 262, inner right armature andback contact of relay 210, outer right armature and backy contact ofrelay 209, armature and front contact of relay 203, armature and frontcontact of relay 202 to grounded conductor 208. Relay 262 encrgizcs andlocks through both. windings and its right armature to groundedconductor 208.

lVhen sequence switch 114 `moves out of position 21/2, relay 202deenergizes and retracts its armature removing the short eircuit raboutthe right hand winding of relay 209. Relay 209 operates in a circuitfrom grounded battery, through the left winding of relay 209, winding ofrelay 207, right Winding of relay 209, inner right front contact andarmature of relay 207 to groimd over conductor 208.

In positions 4l41/ of sequence switch 114, a heavy negative impulse istransmitted from grounded battery, low resistance 144, lower contact ofcam 145, upper contact of negative cam 150 of stations register 109` inparallel With resistance 143, brush 106 and over the circuit previouslydescribed through relays 201, 202, and 203, back to brush 105 and toground over the upper contact of cam 140. In response to this heavynegative impulse, relays 202 and 203 again attract their armatures.`With both of these relays energized, stations relay 264 is actuatedover arircuit from grounded battery, left winding of relay 264, outerright hand armature and back contact of relay 210, outer right armatureand front contact of relay 209, armature and front contact of relay 203,armature andv front contact ofA relay 202, to grounded conductor 208.Relay 264 is energized and at its right front contact and armaturecompletes a, locking circuit Jfor itself from grounded battery throughboth its windings in series to ground over conductor 208.

Relay 202 also completes a holding circuit for relay 209 from groundedbattery, left Winding of relay 209, left hand armature and front contactof relay 209, armature and front contact of relay 202, to groundedconductor 208. Relay 207 is short-circuited and retracts its armatures.lTheshort circuit about relay 210 is maintained at this time hy way ofthe inner right armature and iront contact of relay 209 -to groundedconductor 203. Eis soon as sequence switch 114 leaves position 4%, relay202 becomes ideenergized and the holding circuit for relay 209 isopened. The release rof relay `209 removes the shunt around relay 210and this relay attracts its arniatiires and locks in series lpositionsGabel/gy, no path is closed through low resistance 144 to brush 103 andAalight negative Vpulse is sent from grounded battery through highresistance 143 overthe above traced circuit and hach to ground at theupper contact ot cani 140. Relay 202enei` and energisee relay 207.',Relay 207 attracts its armature to prepare at its in- .ner right troutContact and armature an ein.

ergizing circuit for relay 209, and at its outer front contact andarmature vcompletes an energizing circuit for relay 211 from groundedhatteryyinding ofthis relay, in ner lett armature and back contact ofrelay 213, inner left armature and liront Contact of relay 210, outerright ,armature and lront contact of relay 207 to groundoveij conclue-`tor 203. lWhen sequence switch 114 moves out oi' position 61/2,relay/202 deenergizes und removes the shunt from the right winding ot'relay 209. This relay energizes over its two windings and the winding ofrelay 207 in series. n

lWith sequence switch 114 in positions Tril/fg, a positive impulse istransmitted troni grounded battery, resistance 142, lower Contact of cam132, upper contact ofpositive cam 151 ot' thousands register 110 lower,contact of cam 139, over the previously described circuit and back toground at the` lower Contact ot' cam 140, Relay 201 at# tracts itsarmature and closes a circuit ntroni grounded battery, lei't winding ofthousands lamp relay 323, conductor 302outer right armature and backvcontact of relay 214, outer right armatures and front contacts of relays211 and 206, left armature and front contact of relay 207 `armature andlront contact of relay 201 to grounded conductor 20S. Relay 323 attractsits armatures and completes a locking-circuit for itself from groundedbattery, through both windings in series, its `iight front Contact and yarmature, conductoiw301, inner leftyfront contact and armatureot` relay`200 to ground;

`ter 1-10., ln response jto this weak impulse,

When sequence switch 114 passes through positions 8+81, a light negativeimpulse 1s transmitted from grounded battery, through resistance143,-since the contacts of negative cam 157 -are not closed in "position4 oi regisi'ela'y 202 is enerjigized "closing the holding circuit forrelay 209 and -shunting :relay 207. Relay A`207 rretracts its armaturesbut the shunt around relay 213 is inai-ntainedjatthe inner frighthand,armature of relay 209,` as in the `oaseot relay :210. When-sequenceswitch 114 leaves position S1/2, r elay 202 is deenergized, permittingrelay 209 -to retract its armatures and `rela-y 213 to lock infserieswith relay 211 and thelront contact otrelay 211. to grounded conductor.208, lThis completes `the selec-tion of the thousands lamp controllingrelays, relay323 yalone 'hays` ingv been actuated'.` 1

.Since thehundreds register -is setlinvv positionf, no positive pulsewill be 'set in position 9|91/2 of sequence switch 114. f y

in position inici, i iight negarse pulse is sent in response to whichrelay `202 is energized. Relay 207 is again energized through thelefthand winding of relay 209 and closes a circuit 'for relay2'14extending from grounded battery, winding of relayv 214, inner leftarmature and bac-k` contact of relay 2115, inner' left varmaturesand-front contacts ot relays 2131and 210, outer right armature and frontcontactof relay 207 to grounded conductor 208. Relay 214 at'- tracts itsarmatures and at its .innermost right hand armature and front contactcloses an energizing circuit for Arelay 215.

ith sequence switch 114 in positions 'i 11.4-111/2, no positive Vpulsewill be sent out but when sequence switch 114 leaves ,posif tion 101/2,relay 202 releases and relay 209 operates in series with relay 207.

In positions 12{121/` of sequence switch 114, a heavy negative impulseis, sent out over a circuit extending from grounded hattery, lowresistance, 144 lower contact of cani 147, upper Contact of negativecani 152 of hundreds register 111 Vto brush 106 and thence over theimpulse circuit to ground at the upper contact of cam 140. In responseto this impulse, relays 202 and 203 are en-Y ergized and coni lete acircuit trom grounded battery, left and winding of relay 334, conductor300, outer right armature and back contact of relay 215, outer leftarmatures and front contacts of relays 213 and 210, outer right armatureand front contact of relay 209, armatureand front Contact of relay 203,armature and front contact of relayw202, to ygrounded conductor 208.Relay 334 attracts its armatures and completes a locking circuit Jforitself over conductor, 301 to round.` y elay 202 also completes theholding cir' cuit for relay 209 and shunts `relay'207 'whichrelay"retracts its armatures. 'As soon as Asequence switch 114 moves outof position 1211/2, relay 202 retracts its armatures and relay 209releases, removing the shunt closed atits inner right `hand armature andfront contact around relay 215, and permitting relay 215 to operate inseriesl with relay 214 through the innermost armature and front contactof relay 214 to groundedr conductor 208. This completes the selection ofthe hundredsA lamp controlling relays, relay 334 alone having beenactuated.

It Will now be noted that'the tens register 112 is set in position 6.With sequence switch 114 in position 13+131/, a positive impulse istransmittedfrom grounded battery, through resistance 142, lower contactofcam 133, lower contact of posit-ive cam 153 of tens register 112,upper contact of cam 139, over the circuit previously described toground through the lower Contact of cam 140. Relay 201 is actuated andcompletes an energizing circuit for the tens lamp controllmg relay 341extending from grounded battery, left winding of relay 341, conductor304, middle 'right armature and back contact of relay 217, middlearmature and 'l'ront contact of relay 214, left armatures and frontcontacts of relays 211 and 206, leit armature and back contact of relay207, armature and front contact of relay 201 to grounded couductor 208.'Relay 341 attracts its armature and locks to grounded conductor 301.

With sequence switch 114 in positions 14l141/2, a light negative impulseis transmitted from grounded battery, resistance 143, over thepreviously described circuit to ground through the upper Contact of cani140. -In response to this impulse, relay 202 attracts its armature.Relay 207 is energized in the manner previously described and attractsits armatures to complete a circuit for relay 217 from grounded battery,winding of this relay, inner left armature and back contact of relay218, inner left armatures and front contacts of relays 215, 213 and 210,outer right armature and l'ront contact of relay 207 to groundedconductor 208.

With sequence switch 114 in position 154-151/2, no positive impulse issent out but relay 202 is permitted to retract its arma ture resultingas before in the actuation of relay 209.

In position 164-161/2 of sequence switch 114, a heavy negative impulseistransmitted from grounded battery, resistancev 144, lower contact ofcam k148, upper contact of negative cam 154 of tens register 112 overthe circuit previously traced and back to ground through the uppercontact of cam 140. Relays 202 and 203 are energized. In the mannerpreviously described, relay 207 becomes short-,circuited and retractsits armatures. Relay 344 is also energized over a circuit includinggrounded battery, left hand Winding of relay 344, conductor 306, theouter right armature and back contact of relay 218, the outer leftarmatures and front contacts of relays 215, 213 and 210, outer rightarmature and front contact of relay 209, ar matures and front contactsot' relays 203 and 202 to groundover conductor 208. Relay 344 attractsits armatures and completes a locking circuit for itseltI over conductor301 to ground.

As soon as sequence switch 114 leaves position 161/2, relay 202releases, permitting relay 209 to retract its armatures and relay 218 tolock in series with relay 217 to grounded conductor 208 through theinner most right armature and front contact of relay 217. This completesthe selection of the tens lamp controlling relays, relays 341 and 344having been actuated.

It will vnow be noted that the units sequence switch register 113 hasbeen set in position 8. `Wl1en sequence switch 114 is rotated throughpositions 174-171/2, a positive pulse is sent out over a path fromgrounded battery, resistance 142, upper contact of cani 133, lowercontact of positive cam 150 of units register 113, upper contact of cam130 and over the impulse circuit to ground at the lower contact of cam140. Relay 201 operates in response to this impulse and closes a circuitior units lamp controlling relay 351 which may be traced from groundedbattery, left Winding of relay 351, conductor 309, middle rightarmatures and front coutacts oi relays 217 and 214, left armatures andfront contacts ot' relays 211 and 206, left armature and back contact ofrelay 207, armature and front contact of relay 201 to ground overconductor 208. Relay 351 operates in this circuit and locks to conductor301 through both windings in series and its innermost armature andAfront contact.

In position 18-l181/2, a heavy negative impulse is transmitted fromgrounded battery, low resistance 144, upper contact of cam 149, lowercontact of negative cam 155 of units register 113 over the circuitpreviously described to ground through the upper contact of cam 140. yIn response to this impulse, relays 202 and 203 attract their armatures.Through the front contact of relay 202, the circuit is closed for relay207. Upon the actuation of relay 207, a circuit is closed for relay 219,from grounded battery, winding of this relay, inner left armature andback contact ot relay 221, the inner left armatures and front contactsoi relays 218, 215, 213 and 210, the outer right armature and frontcontact of relay 207 to ground over conductor 208.

In response to this impulse, relay 352 is also operated over a circuittraceable from grounded battery, lett winding of this relay'7 conductor308, inner right armatures and front contacts ot rela'ysa21j8, 215, 213and 210, outer right armature and back contact of relay` 209, armaturesand liront contacts ot relays 202 and 203 rto 'ground over con-` ductor208, Whereuponfrelay 352 locks to grounded conductor 301?. i

l/Vhile sequence switch 11e: is rotated through positions 19.41191/1 nopositive pulse is sent out but relay 202 is permitted to deenergizeagain energizing. relay 209 in theseries circuit `With relay 207 asprevi-` ously described. y Y y ln positions 20+201/2,y ot sequenceswitch114i, a heavy negative impulse is transmitted from grounded.` battery,lower Contact of cam 149, upper contact o'tnegative cam 155 or unitsregister 113 over theimpulse circuit to ground at the upper contact otcam 1410. Relays 202 and 203 yattract their armatures in response tothis impulse and relay 202 completesV a: circuit'itlirough the, right,wind ing of relay 209 andshortcircuits relay 207..

In responsetothis impulse, relay 354 is also operated over a circuittraceable from grounded battery, left Winding .et relay 354-, conductor311,fouter left 'armatures and front contacts 0f'relay218, 215, 218 and210, outer right armature and front Contact ot relay 209, armatures `andiront `contacts ot relays 203 `and 202,"to ground over conductor 208Whereupon'relay 354 locks to ground over conductor `301. l l

As soon as sequence switch 11e leaves position 20% relay 202 becomesdeenergized. lnlresponse' to the retraction or" the armature of relay202, relay 209 becomes' deenergized and at its inner right armature andyiront contact opens the shortcircuit about relay 221 which thereuponbecomes energized in series with relay1219 through the inner `rightarmature and front contact thereof.

When relay 217 operated; it closed a cir.- cuit from ground through itsleft armature and fronti Contact, conductor 222, Windingoi relay 310 -to`,efrrnmded battery. This last mentioned relay `attracts its armaturesto supply battery'for lighting the thousands and hundreds digit lamps.l/Vhen relay 221 attracted its armatures, at its outer lett armature andfront contact, it connected ground to conductor 223 over lWhich thecircuits ot certain of the stations lamps may be completed. At the outerright armature and front contact oi relay 221, a circuit is closed forlighting the selected units indicating lamps; at the outermost rightarmature and front Contact of relay 219, a circuit is closed torlighting the tens indicating lamps and at the outer lett armature andfront Contact of relay 219, a circuit is closed tor lighting. theselected stations indicating lamps.

lt will be remembered that the thousands digit is 4 and that. relay 323has been actuated and locked. When relay 310 attracts inner left:armature and front contact ot relay 323, throughlamp outer lei'tarmatureand "trent contact ot' relay. 323, inner right armature and`frontcontact of relay 810,` to

groundl over conductor 208. The circuits 'l for lighting the hundreds,Vtens and units digits lamps may be 'similarly traced. y

The stations lamp WV vvill be illuminated over a circuit extended fromgrounded battery, outer lettl armature and front contact of relay 219,conductor 224, through lamp WV, outer left armature and front contact ofrelay 262, right armature and front contact of relay 264, to ground`over conductor 208-.

It Willbe understood that as soon asA the impulse 'transmitting device114 has complet'- ed its operation, it Will come to rest andi the cordlin-der rfzoae brushes are designatedby the characters 105 and 106 vasWell as the associated sequencesvvitch `are restored to normal. at" thesame time, a sequence switch, only certain ofthe contacts of which areshown, associated with the trunk selecting switch ismoved rout otposition 11 to open the upper contacts of camsl and1119 and to close thelower contactsolt theseA cams. The B loperator Vupon noting` the numberof the Wanted line inserts the plug l161 into the jack 162 of this lineand depresses the proper ringing key 163 for applying suitable currentto the called'lineto ring the station W which apps-arson this line. TheB operator` releases key 127 and effects the deenergiza.- tion of relays120 and 200. When relay 200 controlling the number indicating deviceappearing in Figs.' 2 and 3 are deenergizcd, due to the removal ofground from vconduc` tors 208 and 301 and the number indicating deviceis placed in condition to indicate a second Wanted line. y The furtherOperation off thefsystem in the completion of the call and therestoration ot' the apparatus on the termination of the call is asdescribed in theabove mentioned Patent No. 1,438,743 to E. H. Clark.

The foregoing description clearly illustrates the application andutility of the present invention in a system of the character disclosedand emphasizes the i'act that. separate generating devices are employedfor the positive and negative impulses Vthat is claimed is: 1. In a codeimpulse transmitting system, a line circuit, means to transmit arecurring` series olE impulses of. the same character thereover, andmeans to modify said series ico 105 retractsy its armatures, theoperatedV relays y s witching device and a register individual toeachsuch generating device.

. 3. In a code impulse transmitting system, a. line circuit, means totransmit a recurring series of impulses of the same character thereover,and means to modify said series of pulses by additional pulses ofopposite polarity or increased potential, there being a separategenerating device for each said character of modifying impulse, eachdevice comprising a switching device and a register individual to eachsuch generating device.

4. In a code impulse transmitting system, a line circuit, means fortransmitting impulses of various characteristics over said line circuit;comprising a plurality of registers, a sourcey of current and aswitching device, there being a separate section of each register and ofsaid switching device for associating said source with said line circuitfor each character of code impulse to be transmitted.

: 5. In a code impulse transmitting system, a line circuit, means fortransmitting impulses of various.characteristics over said line circuitcomprising a source of current, a plurality of sequencel switchregisters and a switching device, there being separate cams on eachregister and on said switching device for kassociating said source withsaid line circuit for each character of code impulse to be transmitted.

6. In a code impulse transmitting system, a source of current, a linecircuit, means to transmit a recurring seriesof impulses thereover fromsaid current source and means to modify said series of impulses byadditional impulses from. said source of various characteristicscomprising a switching device and a plurality of registers, eachcharacter of modifying impulse being generated by the connection of saidsource through an individu al section of said switching device and ofeach of said registers.

7 In a code impulse transmitting system, a source of current, a linecircuit, means to transmit a recurring series of impulses thereover`trom said current source and means to modify said series of impulses byadditional impulses from said source of various characteristicscomprising a sequence switch type switching device and a plurality ofsequence switch registers, each character of modifying impulse beinggenerated by the connection of said source through individual cams onsaid switching device and on each of said registers. f

8. In a code impulse transmitting system, a current source, a linecircuit, means to transmit a recurring series of impulses thereover fromsaid current source and means to modify said series of impulses byadditional impulses from said source of opposite polarity or increasedpotential comprising a switching device and a plurality of registers,each character of modifying impulse being generated by the connectionofsaid source through individual sections of said switching device und ofeachof said registers.

9. In a code impulse transmitting system, a source of current, a linecircuit, means to transmit a recurring series of impulses thereover fromsaid current source and means to modify said series of impulses byadditional impulses from said source of opposite polarity or increasedpotential comprising a sequence switch type switching device and aplurality of sequencev switch re isters, each character of modifyingimpulse ing generated by. the connection. of said source throughindividual cams on said switching device and on each of said registers.

In witness whereof, I hereunto subscribe my name this 16th day of JulyA. D., 1923.

JOHN W. GooDERHAM.

